BackgroundThe evaluation of patients with abdominal discomfort is challenging and patient selection for endoscopy based on symptoms is not reliable. We evaluated the diagnostic value of fecal calprotectin in patients with abdominal discomfort.MethodsIn an observational study, 575 consecutive patients with abdominal discomfort referred for endoscopy to the Department of Gastroenterology & Hepatology at the University Hospital Basel in Switzerland, were enrolled in the study. Calprotectin was measured in stool samples collected within 24 hours before the investigation using an enzyme-linked immunosorbent assay. The presence of a clinically significant finding in the gastrointestinal tract was the primary endpoint of the study. Final diagnoses were adjudicated blinded to calprotectin values.ResultsMedian calprotectin levels were higher in patients with significant findings (N = 212, median 97 μg/g, IQR 43-185) than in patients without (N = 326, 10 μg/g, IQR 10-23, P < 0.001). The area under the receiver operating characteristics curve (AUC) to identify a significant finding was 0.877 (95% CI, 0.85-0.90). Using 50 μg/g as cut off yielded a sensitivity of 73% and a specificity of 93% with good positive and negative likelihood ratios (10.8 and 0.29, respectively). Fecal calprotectin was useful as a diagnostic parameter both for findings in the upper intestinal tract (AUC 0.730, 0.66-0.79) and for the colon (AUC 0.912, 0.88-0.94) with higher diagnostic precision for the latter (P < 0.001). In patients > 50 years, the diagnostic precision remained unchanged (AUC 0.889 vs. 0.832, P = 0.165).ConclusionIn patients with abdominal discomfort, fecal calprotectin is a useful non-invasive marker to identify clinically significant findings of the gastrointestinal tract, irrespective of age.

Fission yeast (Schizosaccharomyces pombe) requires inositol for growth, mating and sporulation. To define putative genes that are involved in the processing and transduction of the inositol signal, mutants that are temperature sensitive for growth and sporulation were selected on a medium containing non-limiting amounts of inositol. Two such mutants (ksg1-208 and ksg1-358) were analyzed, which are impaired in mating and sporulation at 30 degrees C and undergo growth arrest in the G2 phase of the cell cycle at 35 degrees C. The ksg1 gene was isolated by functional complementation. It maps on the left arm of chromosome II and encodes a putative 592-amino acid protein which exhibits good structural homology to a human 3-phosphoinositide-dependent protein kinase (PDK1) and its rat and Drosophila homologues. The two mutants have the same substitution at amino acid position 159: a glycine residue is replaced by glutamic acid. Deletion of the gene is lethal for haploid cells. We propose that ksg1 is involved in one or several phosphoinositide signalling processes that are responsible for control of the life cycle.

Fission yeast, Schizosaccharomyces pombe, is a natural inositol auxotroph. We show here that the amount of exogenous inositol added to the medium is critical for the control of its life cycle. Above growth-limiting concentrations inositol stimulates mating and sporulation in minimal medium. The effect of inositol is also observed on yeast-extract-medium plates. We selected a mutant, IM49, which mates and sporulates only poorly and show that it is defective in inositol transport. Its defect is in a gene (itr2) coding for a putative 12 membrane-spanning protein. The polypeptide contains the two sugar-transport motifs typical for hexose transporters and shows good homology to the two Saccharomyces cerevisiae inositol transporters. The itr2 gene is essential for cell growth and its mRNA level is repressed by glucose. Mutant IM49 is also complemented by a multicopy suppressor gene (itr1) which codes for a putative hexose transporter with unknown substrate specifity.

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